Whether and how the globally available water favours the use of renewable energies and slows down fossil energy sources has been investigated from different perspectives by nine research institutions as well as small and medium-sized enterprises within the framework of the joint project “Water resources as a significant factor of the energy transition on a local and global level – WANDEL”. Among other things, the project partners calculated the water footprint for different energy systems and developed tools for water management. The project, funded by the Federal Ministry of Education and Research over a period of three years, was jointly coordinated by the Ruhr-Universität Bochum (RUB) and the University of Kassel and will be completed at the end of 2020.
It is well known that different energy systems have different water requirements. Direct water consumption, for example for cooling thermal power plants, or the regulation of river flows for hydropower use, influence the local water and environmental systems at the site of the power plant. However, the indirect impacts on water resources in other regions of the world, for example through the mining of coal or copper, are far less well known. The WANDEL project investigated global energy scenarios and their impact on water resources as well as four existing power plant sites in three countries with different energy systems: a coal-fired power plant with water cooling on the Weser, a chain of six run-of-river power plants on the Danube, a solar thermal power plant in Morocco and the use of sugar cane bagasse to generate electricity in Brazil.
Water footprint analysis for different energy systems
The project results show that strategies for transforming the energy system in the context of the energy transition should not only take into account the reduction of greenhouse gas emissions, but also water consumption. Thus, at the global level, scenarios with ambitious targets for a low-carbon energy system do not generally lead to reduced water use. Compared to current conditions, the total volume of water extracted and consumed worldwide for thermal power plants to produce electricity will tend to continue to increase and can only be reduced if the efficiency of power plant and cooling technology increases. This makes thermal electricity production increasingly vulnerable to water scarcity as a consequence of anthropogenic climate change.
The project team conducted a water footprint analysis along the entire energy supply chain, i.e. taking into account local and remote water demand, and thus compared the water consumption per unit of energy generated for different energy systems. The analysis showed that energy production based on renewable raw materials, for example, has a very high water footprint. Integrated systems using waste materials (in this case sugar cane bagasse) to generate energy can significantly reduce the water footprint. Risk and sustainability analyses show that energy supply is becoming more vulnerable with increasingly frequent water scarcity and drought under climate change conditions. Especially in arid regions, water is already a scarce resource and a limiting factor for economic growth and agricultural production. There, the health of people and ecosystems, sustainable energy production and water supplies are at risk in a changing environment. As hydropower generation impacts freshwater megafauna, biodiversity should also be considered when assessing low-carbon energy transition strategies.
New tools for the practice
To address the identified problems, the WANDEL project team, together with practice partners, developed several technical and governance tools: a new tool for water management and a simulator for training power plant staff. These tools enable optimal control of dams and impoundments and increase the efficiency and safety of waterways and impounded watercourses. A new approach, Environmental Sustainability Assessment, extends environmental impact assessment and allows the sustainability of anthropogenic processes to be assessed with upstream supply chains. A set of indicators for determining the vulnerability of energy systems and water resources supports decision-makers in assessing the sustainability of measures taken in the context of energy and water security.
Finally, the WANDEL project follows an open data approach. All data generated within the project will be made available to the public on the WANDEL-Share platform. The project’s open data policy provides a solid basis for robust decision-making in the context of the transition to low-carbon energy systems.